Promising to balance agriculture and the environment, Interior Secretary Bruce Babbitt took a sledgehammer to a concrete dam on Butte Creek that bars salmon from spawning.

"This is one small step for the salmon run and one large blow for the future of California and its environment," Babbitt said Tuesday.But he also suggested a new approach for some of the 75,000 dams in the country, including 3,000 in California. Many were built decades ago and are no longer needed, particularly if fish are to be protected, Babbitt said.

"Dams are not like the pyramids of Egypt. They do not stand for eternity. We find over the years there are different conditions and different needs, and hopefully we will respond to them," he said.

The ceremony at McPherrin Dam, about 25 miles south of Chico, marked the beginning of a project to remove two dams and restore 20 miles of Butte Creek to an unimpeded flow for the first time since the 1920s. The removal should be complete this summer.

Butte Creek, which flows into the Sacramento River, is one of only four tributaries that still have spring-run chinook salmon. The dams make it difficult - if not impossible - for the fish to return upstream to lay eggs.

"You can't spawn your way over a concrete dam," Babbitt said.

The Western Canal Water District, which owns the irrigation diversion dams, is working with state, federal and water agencies on the project.

Local ranchers, who guard their water sources carefully, did not oppose the removal of the dam since they can get water from another diversion. About 50 officials and local farmers attended the ceremony.

"I think it represents a spirit of hope for California to find a better balance between agriculture, recreation and the environment," Babbitt said.